I'd rest until you've got your test results back.
It's scary. I've had Pneumonia and TB in the past.
Infection that causes your lymph nodes to swell can cause breathing difficulties, so can other conditions, that can be treated. It isn't necessarily a lung issue.
I had very low Vit B once and couldn't breath. I had injections and it solved it.
They will get to the cause and you will feel better again.